An investor owns 1000 American Call Options over Repsols shares. The strike price is 15$ per share and the premium paid is 0.5$ per option. Today the quotation of the Repsols shares is 18.5$. If the investor decides to exercise the options which is the gain of the investor: A) 3,500$ B) 3,000$ C) 500$ D) Depends on the time until maturity